Phone:
0086 28 87573647
+86 19150187139
High-performance liquid chromatography (HPLC) is an effective and reliable technique that has become an important tool in many laboratory research settings. One of the most common problems with HPLC is the impact of contaminants in the solvent on the analytical results.
First, let's look at some common contaminants:
1. Visible Impurities
Visible impurities can damage pumps and syringes, clog and melt the column, leading to increased back pressure. Particles can also act as another solid phase, potentially altering the sample composition.
2. Organic Matter
Organic matter in ultrapure water can affect peak resolution and integration, potentially causing ghost peaks, altering the selectivity of the stationary phase, and affecting the chromatographic baseline.
3. Ions
Changes in ion concentration can affect separation results. Some ions that absorb UV light can influence peaks. Certain corrosive ions can also reduce the lifespan of high-pressure pumps and other components.
4. Colloids
Colloids can irreversibly adsorb onto the stationary phase, affecting column separation performance.
5. Microorganisms
Microorganisms can clog chromatographic columns, and their metabolic products increase contaminants such as organic matter and particulate matter.
Currently, some HPLC analyses use purified water and distilled water. However, since purified water and distilled water are only ordinary pure water, not ultrapure water, they still contain small amounts of ions and organic matter. Using them to prepare HPLC phases and eluents can not only clog expensive chromatographic columns but also affect the establishment of a flat baseline in HPLC.
Purification processes for purified water include adsorption, filtration, and reverse osmosis, which have a certain removal effect on particulate organic matter. However, they are insufficient for removing trace ions and organic matter in high-sensitivity HPLC. Furthermore, if improperly stored, the water quality deteriorates further. Therefore, in HPLC chromatograms, although there may be no specific absorption peak, the baseline exhibits significant instability interference.
Distilled water refers to pure water prepared by distillation. It can be divided into single-distilled and multi-distilled water. After single distillation, non-volatile components remain in the container and are removed, while volatile components enter the initial fraction of the distilled water. Typically, only the middle fraction, approximately 60%, is collected. To obtain purer water, an alkaline potassium permanganate solution can be added to the single-distilled water to remove organic matter and carbon dioxide; a non-volatile acid (sulfuric acid or phosphoric acid) can be added to convert ammonia into a non-volatile ammonium salt. HPLC analysis of double-distilled water revealed strong absorption peaks at 254 nm and 214 nm between 22 and 27 minutes, indicating contamination by highly hydrophobic organic compounds. This is likely due to the azeotropic effect during distillation, leading to incomplete removal of some volatile organic compounds.
In conclusion, to achieve high-sensitivity HPLC and stable, accurate analytical results, the use of ultrapure water in HPLC analysis is recommended.
Sichuan Youpu Ultrapure Technology Co., Ltd.'s ultrapure water system integrates multiple purification processes, including reverse osmosis, ion exchange, activated carbon adsorption, membrane filtration, terminal filtration, and ultraviolet oxidation. Online resistivity monitoring reaches 18.2 MΩ•cm, ensuring stable and measurable water quality. The ultrapure water produced is ready for immediate use, preventing contamination during storage and guaranteeing water quality. It better meets users' needs for high-precision instrument analysis. For more details, please call our customer service hotline at 400-884-6567.
